Pathological evidence of pancreatitis in 43 horses (1986-2011).

REASONS FOR PERFORMING STUDY: Definitive ante mortem diagnosis of pancreatitis in horses is difficult. Reports summarising the most common clinical signs, clinicopathological features and concurrent disorders in horses with a definitive diagnosis of pancreatitis that may aid in the recognition of disease are lacking. OBJECTIVES: To describe case details, clinical signs, clinicopathological data and necropsy findings in horses with a definitive diagnosis of pancreatitis. METHODS: This was a retrospective study (1986-2011) and inclusion criteria consisted of horses with a definitive diagnosis of pancreatitis. A medical records database search was performed and data extracted included case details, clinical signs, clinical laboratory data and post mortem findings. Pancreatitis was defined as acute, active chronic or chronic and presumed primary or secondary, based on postmortem findings. RESULTS: Pancreatitis was diagnosed in 43 horses (acute pancreatitis in 34, active chronic in 4 and chronic in 5). A presumed diagnosis of primary pancreatitis was made in 6 horses. Pancreatitis was associated with gastrointestinal disorders in 28 horses (14 large colon, 10 small intestine and 4 gastric ruptures) and primary hepatic disease in 3 horses. Six horses had pancreatitis associated with other disorders: multiple endocrine neoplasia syndrome (one horse), strychnine toxicosis (one horse) and compromised immune system (4 horses). CONCLUSION: Pancreatitis is an uncommon disorder that can occur as a primary problem or secondary to gastrointestinal, hepatic or immunocompromising disorders, and when it occurs it affects adult horses more commonly. POTENTIAL RELEVANCE: Unexplained abdominal pain, gastric dilation or rupture, peritonitis and/or the presence of white fibrinous plaques and fat necrosis in the peritoneum and mesentery or mass-like structures in the root of the mesentery during an exploratory celiotomy should raise a suspicious of pancreatitis.

Antibodies to elastin peptides in sera of Warmblood horses at different ages.

REASONS FOR PERFORMING STUDY: Early diagnosis and monitoring progression of chronic diseases in elastin-rich tissues, such as chronic progressive lymphoedema in draught horses and chronic obstructive pulmonary disease (COPD) is still a real challenge in the horse. Use of an enzyme-linked immunosorbent assay (ELISA) to detect anti-elastin antibody (AEAb) levels might be useful to assess the status of such diseases. Baseline levels, representing physiological breakdown of elastin in normal horses, are not available at present. HYPOTHESIS: Levels of AEAb in healthy horses are generally low and follow the same age-related pattern as found in man. Therefore, elevation of AEAb levels in serum can be used to evaluate pathological elastin breakdown in elastin-rich tissues. METHODS: Sera of 84 clinically healthy Warmblood horses were evaluated for the presence of AEAbs by means of a modified version of an ELISA technique used in man. The horses were divided in 5 age groups: A) < 4 months; B) 4-23 months; C) 2-3 years; D) 4-10 years; and E) > 11 years. RESULTS: Antibodies to elastin were found in all equine serum samples tested. Their levels were lowest in Group A, low in Groups B and E and highest in animals age 2-10 years. CONCLUSIONS: Measuring AEAbs in serum of horses by an ELISA technique proved to be possible and levels were stable during well-defined life stages. POTENTIAL RELEVANCE: Changes in AEAb levels are expected to be useful for early diagnosis and for monitoring progression of diseases that affect elastin-rich tissues, such as chronic progressive lymphoedema and COPD.

Antibodies to elastin peptides in sera of Belgian Draught horses with chronic progressive lymphoedema.

REASONS FOR PERFORMING STUDY: Chronic progressive lymphoedema (CPL) is a recently recognised disease of the lymphatic system characterised by lesions in the skin of the lower legs in several draught horse breeds, including the Belgian Draught hourse. Clinical signs slowly progress and result in severe disfigurement of the limbs. Ideally, supportive treatment should be started early in the disease process. However early diagnosis and monitoring progression of CPL is still a challenge. HYPOTHESIS: Elastin changes, characterised by morphological alterations as well as increased desmosine levels, in the skin of the distal limbs of horses affected with CPL are probably associated with a marked release of elastin degradation products, which elicit production of circulating anti-elastin antibodies (AEAbs) in the serum. An enzyme-linked immunosorbent assay (ELISA) for detection of serum AEAbs may document elastin breakdown. METHODS: An ELISA technique was used to evaluate levels of AEAbs in sera of 97 affected Belgian Draught horses that were clinically healthy except for possible skin lesions, associated with CPL in their distal limbs. The horses were divided into 5 groups according to the severity of these skin lesions: normal horses (Group 1, n = 36), horses with mild lesions (Group 2, n = 43), horses with moderate lesions (Group 3, n = 8), horses with severe lesions (Group 4, n = 10) and, as a control, healthy Warmblood horses, unaffected by the disease (Group 5, n = 83). RESULTS: Horses with clinical signs of CPL had significantly higher AEAb levels compared to clinically normal Belgian Draught horses and to healthy Warmblood horses. These levels correlated with severity of lesions. CONCLUSIONS: CPL in draught horses is associated with an increase of serum AEAbs. POTENTIAL RELEVANCE: Evaluation of serum levels of AEAbs by ELISA might be a useful diagnostic aid for CPL. Pathological degradation of elastic fibres, resulting in deficient support of the distal lymphatics, is proposed as a contributing factor for CPL in Belgian Draught horses.

Prevalence and histopathologic characteristics of pancreatitis in cats.

Despite the high prevalence of feline pancreatic disease, no detailed description on the histopathologic nature of this disease is currently available in the literature. In this study we characterize the distribution and histopathologic changes commonly found in feline pancreases, correlate the lesions with age and gastrointestinal GI and extra-gastrointestinal disease, and compare the pancreatic lesions in cats with those in humans. The entire pancreas was removed and examined from 115 cats presented for necropsy irrespective of the cause of death. Histologic sections from left limb, right limb, and body were scored for lesions of acute (AP) and chronic pancreatitis (CP) with a scoring system based on similar systems used in human and veterinary literature. The lesions of CP in cats resemble CP in humans, with fibrosis being more prominent than inflammatory changes. Cystic degeneration gradually increased as other lesions of CP were more prominent. A distinct nodular change of zymogen depletion and acinar cell dysplasia not associated with pancreatitis was prominent in 15.6% of the pancreases. Histologically, AP consisted of neutrophilic inflammation associated with interstitial edema and necrosis of mesenteric fat. An overall prevalence of 67%, and 45% in clinically normal animals, was identified. CP was found in 69 (60.0%) pancreases, and 58 (50.4%) had CP only, with a significant correlation between age and occurrence of CP. There was a statistically significant higher prevalence of CP in the left limb in animals with gastrointestinal disease. AP was present in 18 animals (15.7%) of which 7 animals had AP only (6.1%).

Lymphoscintigraphy of draught horses with chronic progressive lymphoedema.

REASONS FOR PERFORMING STUDY: Early diagnosis of chronic progressive lymphoedema (CPL) may result in more effective interventions and provide a basis for further investigation of whether early diagnosis could be used as a means of eliminating potential genetic influences by cessation of breeding from affected individuals. HYPOTHESIS: Lymphoscintigraphy may be useful in draught horses to differentiate early lesions of CPL from other conditions in the pastern region. METHODS: Forelimbs of 2 normal and 5 CPL-affected draught horses were evaluated with lymphoscintigraphy. RESULTS: Lymphoscintigraphy showed clearly the presence of interstitial fluid stasis and delayed lymphatic drainage in the affected extremities of diseased animals in contrast to normal animals of these breeds. The rate of decreased clearance of a particulate radiopharmaceutical from the tissues was related positively to the severity of clinical signs. CONCLUSIONS AND POTENTIAL RELEVANCE: Our findings support the hypothesis that lymph stasis is probably responsible for the progressive swelling and concurrent skin lesions observed in association with CPL in draught horses. Lymphoscintigraphy should also prove useful in diagnosis of CPL in draught horses, even in the mild stages of the disease; such early diagnosis may result in more effective intervention.

Metastatic tumors to the adrenal glands in domestic animals.

Although metastases to the adrenals are common in humans, they have not been thoroughly studied in animals. The purpose of this retrospective study was to document the types of malignant tumors that metastasize to canine, feline, equine, and bovine adrenals, and the rate at which they do so. The average rate of adrenal involvement in metastatic cancer was 112/534 (21.0%) in dogs, 12/81 (14.8%) in cats, 18/67 (26.9%) in horses, and 5/16 (31.3%) in cattle. In dogs, 26 different tumor types metastasized to the adrenals. Pulmonary, mammary, prostatic, gastric, and pancreatic carcinomas, and melanoma had the highest rates of metastasis to the adrenal glands in dogs. Hemangiosarcoma and melanoma had high rates of adrenal involvement in horses. In cats and cattle, relevant data were only available for lymphoma. Adrenal metastases usually occurred in the late stages of the disease. One dog had developed Addison's disease (hypoadrenocorticism) secondary to lymphoma. Metastatic lesions represented 126/472 (26.7%) of canine, 12/20 (60.0%) of feline, 21/80 (26.3%) of equine, and 5/9 (55.5%) of bovine adrenal neoplasms. This study shows that adrenal glands should be thoroughly examined during both clinical work-up and postmortems when disseminated neoplasia is suspected.

Indicators of malignancy of canine adrenocortical tumors: histopathology and proliferation index.

Tumors of the adrenal cortex account for 10-20% of the naturally occurring Cushing's syndrome diagnosed in dogs. Differentiating between adrenocortical adenoma and carcinomas is often difficult. The purposes of this study were to determine which histopathologic criteria can be used as markers for malignancy in canine adrenocortical tumors and the relevance of the proliferation marker, Ki-67, for differentiation between cortical adenomas and carcinomas. Twenty-six adrenocortical carcinomas, 23 adenomas, and 11 normal adrenal glands were examined. Morphologic criteria significantly associated with adrenocortical carcinomas included a size larger than 2 cm in diameter, peripheral fibrosis, capsular invasion, trabecular growth pattern, hemorrhage, necrosis, and single-cell necrosis, whereas hematopoiesis, fibrin thombi, and cytoplasmic vacuolation were significantly associated with adrenocortical adenomas. The mean (+/- SD) proliferation index, measured by immunohistochemistry for the Ki-67 antigen, was 9.3 +/- 6.3% in carcinomas, 0.76 +/- 0.83% in adenomas, and 0.58 +/- 0.57% in normal adrenal glands. The Ki-67 proliferation index was significantly higher in carcinomas compared with adenomas and normal adrenal glands. A threshold value of the proliferation index of 2.4% reliably separated carcinomas from adenomas. Based on these results, it appears that thorough evaluation of morphologic features combined with immunohistochemical assessment of the proliferation index is extremely useful for differentiating between adrenocortical adenomas and carcinomas in dogs.

Immunoglobulin A monoclonal gammopathy in two horses with multiple myeloma.

The clinical findings in two horses with secretory multiple myeloma and secondary immunoglobulin A (IgA) monoclonal gammopathy were non-specific and included weight loss, pale mucous membranes, limb oedema and bacterial respiratory tract infection. Consistent laboratory abnormalities included hyperproteinaemia, hyperglobulinaemia, hypoalbuminaemia and hypercalcaemia. The diagnosis was based on the presence of IgA monoclonal gammopathy in serum and urine and bone marrow plasmacytosis (> 10 per cent). One horse was euthanased; it had neoplastic plasma cell infiltrates in its kidneys, spleen, liver, bone marrow, myocardium and adrenal glands. The other horse was treated for a bacterial pneumonia and was still alive six months after it was first examined.

A peripheral primitive neuroectodermal tumor with generalized bone metastases in a puppy.

A peripheral primitive neuroectodermal tumor (pPNET), most consistent with a human Ewing's sarcoma, is described in a 5-month-old male Australian Shepherd puppy. The first tumor site detected was in the left frontal bone of the skull with apparent subsequent rapid metastases to multiple sites in the axial and appendicular skeleton and bone marrow, kidneys, and perihyphophyseal meninges. Radiographically, all bone lesions were lytic and there was also a humeral bone fracture. Histologically, the tumor was diagnosed as a small round blue cell tumor. At this stage, the differential diagnosis included a lymphoma, rhabdomyosarcoma, and a PNET of the peripheral nervous system. However, the cells had positive expression of triple neurofilament antigens as detected immunocytochemically. The cells were negative for a broad panel of canine-specific leucocyte cell marker antigens for desmin, smooth muscle actin, synaptophysin, and CD99. Ultrastructurally, the cells contained occasional dense core neurosecretory granules and intermediate filaments with intercellular desmosomal-like junctions and abundant glycogen clusters. Based on the age of the dog, the clinical history, the distribution of gross lesions, histologic characteristics of a small round blue cell tumor, and immunocytochemical and ultrastructural evidence of neuroectodermal differentiation, a diagnosis of a pPNET similar to a human Ewing's sarcoma was made.

Ileocolitis associated with Anaerobiospirillum in cats.

Ileocolitis associated with spiral bacteria identified as an Anaerobiospirillum sp. was found in six cats. Two cats had acute onset of gastrointestinal signs characterized by vomiting and diarrhea in one cat and vomiting in another cat, one cat had chronic diarrhea that was refractory to medical therapy; one cat had acute onset of anorexia and lethargy, and two cats had clinical signs that were not related to the gastrointestinal tract. The presence of an Anaerobiospirillum sp. was demonstrated on the basis of ultrastructural morphology of spiral bacteria associated with intestinal lesions and PCR amplification of a genus-specific 16S rRNA gene from affected tissues from each cat. The colons of three clinically healthy cats without lesions and one cat with mild colitis not associated with spiral bacteria were negative for Anaerobiospirillum spp. in the same assay. Comparative nucleotide sequence analysis of cloned PCR products from three affected cats further suggested that the spiral bacteria were closely related to Anaerobiospirillum succiniciproducens.

Ovarian papillary cystadenocarcinomas in a green iguana (Iguana iguana).

The clinical, gross morphological and histological characteristics of bilateral ovarian papillary cystadenocarcinomas in an adult female green iguana (Iguana iguana) are documented in this report. Histologically, the tumour consisted of an invasive mass of small glandular structures, irregular arboriform papillae and cystic structures arising from the ovarian surface epithelium. Metastatic implants were extensively disseminated along the serosa of the coelomic viscera, mesentery and fat bodies. Tumour morphology and metastatic behaviour indicated a close resemblance to cystadenocarcinoma in other species. Primary ovarian neoplasia is rare in reptiles; documented cases include tumours arising from surface epithelium, germ cells and sex cord stroma.

Ameloblastic carcinoma in a horse.

The clinical, gross morphological, histological and immunohistochemical characteristics of an ameloblastic carcinoma in a 30-year-old Quarter Horse mare are reported. This tumour was fast growing, locally invasive and destructive. Histologically, it showed an infiltrative pattern of large islands, broad sheets and, at the periphery, small cords of moderately pleomorphic round, oval to spindle-shaped cells. Immunohistochemical evaluation revealed positive labelling for vimentin, cytokeratin 5/6 and cytokeratin 14. In the oral cavity of human beings, this immunolabelling pattern is unique for the embryonal enamel organ and tumours of ameloblastomatous epithelial origin, which strongly supports the diagnosis of equine ameloblastic carcinoma.